This invention relates generally to dishwashers, and more particularly, to drying cycles for dishwashers.
Typically, known dishwashers include a cabinet housing a wash chamber wherein dishes, flatware, cups and glasses, etc. are loaded onto roller-equipped racks. Washing fluid is circulated throughout the wash chamber according to a pre-designated wash cycle executable by a control mechanism. Often, the wash cycle concludes with a dry cycle that operates a heating element located within the wash chamber, as well a forced air convection system that circulates ambient air through dishwasher vents to remove humidity from the wash chamber and dry the items located therein. Conventionally, the dry cycle consists of operating the heater element and the circulation fan for a fixed time period and opening the vent for a predetermined time period. See, for example, U.S. Pat. No. 3,908,681.
While in most cases, fixed duration heating cycles may adequately dry items in the dishwasher, certain operating conditions can render the dry cycle inadequate and/or undesirable. For example, water temperature variations in dishwasher rinse cycles, which may occur for various reasons, may lead to incompletely dried items at the end of the cycle or completely dried items well in advance of when the cycle ends. Also, rinse aid products are now available that may affect the amount of time required to dry items in the dishwasher. See, for example, U.S. Pat. No. 6,210,600 B1. Hence, the presence or absence of the rinse aid may result in dry cycles that are excessive or inefficient, respectively.
In light of stringent new energy efficiency requirements and expectations, inefficient dry cycles are undesirable for both manufacturers and consumers alike.
In one aspect, a method for controlling a dry cycle for a dishwasher including a wash chamber and a heater element in the wash chamber is provided. The method comprises sensing a temperature of the wash chamber, and energizing the heater element for a time dependent upon the sensed temperature.
In another aspect, a method for operating a dishwasher in a variable dry cycle mode is provided. The dishwasher includes a wash chamber, a heater element located within the wash chamber, a rinse aid product dispenser, and a fan unit for circulating air. The method comprises determining a temperature of the wash chamber, determining an amount of rinse aid product in the dispenser, and, based upon the determined temperature and the amount of rinse aid product, determining an optimized heater element cycle and an optimized fan unit cycle.
In yet another aspect, a method for operating a dishwasher in a variable dry cycle is provided. The dishwasher includes a wash chamber, a heater element in the wash chamber, a rinse aid product dispenser, a fan, and a controller. The method comprises determining operating conditions of the wash chamber and the rinse aid dispenser, and operating the heater element and the fan to execute an energy efficient dry cycle dependent upon the determined conditions of the wash chamber and the rinse aid product dispenser.
In a further aspect, a dishwasher is provided which comprises a wash chamber, a thermistor for determining a temperature of said wash chamber, a heater element located within said wash chamber, and a controller operatively coupled to said heater element and to said thermistor, said controller configured to operate the heater element for a selected time period determined by a thermistor reading.
In still a further aspect, a dishwasher is provided which comprises: a wash chamber, a thermistor for determining a temperature of said wash chamber, a heater element located within said wash chamber, a fan unit, and a controller operatively coupled to said heater element, to said thermistor, and to said fan unit. The controller is configured to execute a variable dry cycle wherein the heater element is energized for a selected time period determined by a thermistor reading and the fan is energized for a selected time period determined by the thermistor reading.
In yet an additional aspect, a dishwasher is provided which comprises a wash chamber, a thermistor for determining a temperature of said wash chamber, a heater element located within said wash chamber, a fan unit, a rinse aid product dispenser, a transducer operatively coupled to said rinse aid product for determining an amount of rinse aid product in the dispenser, and a controller operatively coupled to said heater element, to said thermistor, to said fan unit, and to said transducer. The controller is configured operate an energy efficient dry cycle wherein said fan unit and said heater element are energized for a time determined in response to signals from said thermistor and said transducer.